The new spot, which airs on cable networks, mocks Mitt Romney for saying during last week’s debate that he would cut public funding to the Public Broadcasting Service – even though he likes Big Bird.

But Sesame Workshop – the nonpartisan nonprofit behind Sesame Street – wasn’t pleased. In a statement, Sesame Workshop objected to the ad: “We have approved no campaign ads, and, as is our general practice, have requested that both campaigns remove Sesame Street characters and trademarks from their campaign materials.”

The ad begins with an ominous voiceover listing the names of Wall Street criminals, including Bernie Madoff and Kenneth Lay. The deep, dramatic voice then says, “It’s not Wall Street you have to worry about; it’s Sesame Street.”

The camera then cuts to a shot of Big Bird sleeping.

President Barack Obama has seized on Romney’s Big Bird comment to argue that his Republican challenger would crack down on beloved American institutions such as Sesame Street but would allow Wall Street to run wild.

Speaking to a crowd of 15,000 in Columbus, OH the President said, “Today (Romney) decided we’re going after Big Bird. Elmo’s making a run for the border and Oscar is hiding out in a trash can.”

Emphasizing the Sesame Street theme, recording artist will-i-am kicked off his performance at the Ohio event by playing the Sesame Street theme song.

The Obama campaign has also dispatched Big Bird mascots to stand outside Romney campaign events and even Michelle has entered the fray. On Tuesday, the first lady told supporters in Loudon, Va.: “We all know good and well that cutting Sesame Street is no way to balance a budget.”

Speaking in Van Meter, Iowa, Romney fired back: “These are tough times with real serious issues. You have to scratch your head when the president spends the last week talking about saving Big Bird.”

The Romney campaign noted that Obama has in recent days made more public references to Big Bird than Libya – where the U.S. consulate was recently attacked and the ambassador killed.

But the Obama campaign stands by its strategy.

“The point we’re making here is that when Mitt Romney was given the opportunity to lay out how he would address the deficit … his first offering was to cut funding to Big Bird and that is absurd and hard to take seriously,” Obama campaign spokeswoman Jen Psaki told reporters.

With polls showing Romney improving since the debate, it remains to be seen whether the president’s “Big Bird Offensive” will sway undecided voters.